Air-blast heater.



E. HOHMANN.

AIR BLAST HEATER.

APPLICATION FILED MAR.25. 1912.

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AIR BLAST HEATER.

APPLIOATION FILED mama, 1912.

1,079,764. I Patented Nov. 25, 1913.

3 SHEETS-SHEET 2.

E. HOE-MANN.

AIR BLAST HEATER.

APPLICATION FILED MAILZS, 1912.

1,079,764. Patented Nov. 25, 1913.

3 SHEETS-SHEET 3.

v UNITED STATES PATENT OFFICE.

EDMUND HOHMANN, 0F STETTIN, GERMANY, ASSIGNOR TO STETTINER C HAMOT'IE- FABRIK ACTIEN-GESELLSCHAFT VOBM. DIDIER, OF STETTIN, GERMANY, A. CORPO- RATION 0F GERMANY.

AIR-BLAST HEATER.

Specification of Letters Patent.

Patented Nov. 25, 1913.

Application 'filed larch 25, 1912. Serial No. 685,974.

such as are used to heat the blast or air for blast furnaces.

The object of my present invention is to improve the operation of such devices by securing favorable conditions as regards the supply of air to support combustlon durmg one period of operation and the conveying away of the hot blast during the other period. It is well understood that stoves of this character are operated in two alternating periods, during the first of which the stove is heated by the combustion of fuel, while during the second period cold air is passed through the stoveto absorb the heat stored during the preceding period.

My present invention comprises devices for regulating the supply of fuel and air during one period, and the delivery of hot air during the other period, and insures a uniformly efiicient operation, as will be set forth in detail hereinafter.

Reference is to be had to the accompanying drawings, representing, as an example, one form of my improved air-blast heater.

Figure 1 is a vertical section on line AB of Fig. 2, Fig. 2 is a horizontal section on line CD of Fig. 1; Fig. 3' is a horizontal section, taken on line E-F of Fig. 4; and showing a slightly different arrangement of fines; and Fig. 4 is a vertical section through the lower part of the stove, taken on line GH of Fig. 3. i

The stove or. heater shown comprises a series of concentric walls 4, 5,. 6, 7 forming nested annular chambers 11, 2, 3 and a central space or shaft 9, the latter filled with checkerwork. A dome 8 extends over the upper ends of the shaft 9 and of the innermost chamber 3, said upper ends communicating with each other. An annular cover 10 extends over the upper ends of the outer chambers 1 and 2. The chambers 1, 2, 3 are divided by radial partitions 16 into segmental fiues 17 18,- and 19 respectively. The fines of the same radial group, or in other words, those lying between the sameadjacent partitions 16, are connected in series,

suitable tools which that is to say, alternately at opposite ends, so as to compel the combustion gases (or the air during the heat-absorbing period) to pass'successively in a sinuous path through the. several flues of the same radial group. Of course, the partitions 16 are extended to the bottom 14 and to the annular cover 10. During the combustion period, fuel such as gas is supplied from the annular conduit 38 placed around the lower part of the heater,

through branch conduits 37 (preferably equal in number to the flue groups) to individual chests 28, each located in one of the outermostflues 17 and provided at.the top with a burner outlet 31 formed as a segmen- -talslit. Adjacent to each of the slits 31, a

similar slit 32 for the admission of air intended to support combustion is formed between the inner wall of the chest 28 and a suitable projection on the outer surface of the heater wall 5. The effective width of the slits 31, 32 may be varied by a suitable adjustment of the slides 33 and 34 respectively, the slides being adjustable independently in the several flues 17. The slides 33, 34: are adjusted by means of rods or other may be introduced through openings 61 located in the outer: wall 4 between the pipes through which the heating gas flows from the conduit 38 to the chests 28, and the branch conduits 60 through which the hot blast passes out. The outer portions of the openings 61 are enlarged as shown in Figs. 1 and 4, to receii e slabs or plugs 62 normally closing said openings, and these plugs may have sheetmetal covers 63 corresponding to the metal lining which surrounds the stove. After the slides 33, 34 have been adjusted, they need not be disturbed again. The bottom of the central space or shaft 9 communicates with the channel 41 which during one period serves to carry the combustion products to the chimney or other outlet, while during the next period the cold air to be heated is led in through said channel 41.

A second annular conduit 58 is shown above the conduit 38, and from this conduit 58 separate branch conduits 60 lead to the individual outermost flues 17, the effective cross section of each branch conduit being adjustable independently by means of regulating devices, such as the slides 59. The branch conduits 6O connect with the respective fines 1'? at points above the burners formed by the fuel-supply slits 31 and the air-supply slits 32. Finally, a third annular conduit 51, located above the conduit 58, has individual connections 53 regnlatable by slides 52 or other suitable devices. These connections 53 are equal in number to the fines l7 and lead to the lower ends of ascending upright channels 54 extending a considerable distance within the outermost wall 4 of the heater. At their upper ends the channels 54 are connected by transverse ducts 55 with descending channels 56 likewise located within the outermost wall 4 and made of a smaller cross section than the ascending channels 54. The descending channels 56 lead to the lower ends 57 of the corresponding flues 17.

The air intended to support combustion is supplied, as by a pipe 11, to the annular conduit 51, passes through. the branch conduits 53 to the individual channels 54, and then through the ducts 55 to the descending channels 56 and to the lower ends 57 of the fines 17. Owing to the difi'erence in the cross section of the channels 54 and 56, the air will travel more slowly in the ascending channels 54, so as to insure its thorough heating by the hot outer wall 4. The air being well heated in the channels 54, may then be conducted at a greater speed through the channels 56 which are of smaller cross section.

The fuel (gas) is supplied to the annular conduit 38, as by a pipe 12, and passes through the branch conduits 37 to the fuel chests 28 and out into the fines 17 through the slits 31, while at the same time heated air passes upward from the lower portions 57 of the fines 17 through the slits 32 which are adjacent to the slits '31. The mixture of fuel and air burns in the fines 17, and the hot combustion products pass successively through the fines 17, 18 and 19 and the shaft 9 and channel 41, thus heating the walls 4, 5, 6, 7 and the checkerwork in the shaft 9. It will be understood that during this combustion period the slides or valves 52 and 36 are open, while the slides or valves 59 are closed.

After a suitable lapse of time, the valves 52 and 36 are closed, the valves 59 opened. and the channel 41 is disconnected from hilt. stack or chimney and connected with an airsupply, in the well-known manner. During this heat-absorbing eriod the cold air therefore passes into tie shaft 9 of the heater through the channel 41, then flows through the several groups of fines 19, 18,

17, and the hot air passes through the branch conduits 60 and the annular collector conduit 58 to the place of use, say throu gh a pipe 13. k

A uniform heating is obtained during the combustion period by a proper adjustment of the regulating devices 52 and 36, which is of importance particularly in view of the fact that the several connections 53 and 37 are located at different distances from the air inlet pipe 11 and the fuel supply pipe 12 respectively. The slides 33, 34 afford an additional means of regulating the supply of fuel and-air respectively to the individual fines 17. Similarly, the regulating devices 59. enable me to obtain a uniform distribution and heating of the cold air during the heat-absorbing period, particularly in view of the fact that the branch conduits 60 are at different distances from the outlet pipe 13. The fact that the outlets 60 for the hot blast are above the slits 31, 32 is an advantage since I thereby avoid forcing the hot blast through narrow slitlike openings, as would be the case if the conduit 51 were used as an outlet for the hot blast. In this manner I avoid, as far 'as possible, obstruction and checking of the hot blast in the heater, and the resulting fluctuations of pressure in the hot blast pipe connected with the outlet pipe 13.

My invention provides means for individually adjusting the flow of combustion products and of air in each of the several groups of fines 17 18, 19, and also the relative supply of fuel and air to each of the flues 17, so as to secure a maximum utilization of the masonry of the heater.

In some cases it may not be necessary to carry the hot blast through a separate branch conduit 60 from each of the outermost flues 17 but a single common outlet to the collector 58 may be provided for two or more fines 17. In such case some or all of the partitions 16 would be perforated in the outermost chamber 1 at the level of the outlet branch conduits 60, (as indicated at 64) thereby forming a segmental or an nular channel communicatin with two or more fines 17 (even all of them), the hot blast being then carried away from this channel at several points. This and other modifications may be made without departing from the nature of my invention as set forth in the appended claims. Thus, at the right-hand portion of Fig. 3, groups of three fines 17 are connected with a common branch conduit 60, while at the left-hand portion of said figure all the partitions 16 are shown provided with openings 64, and only two branch conduits 60 are provided for this half of the oven.

I claim:

1. An air-blast heater comprising walls forming a central shaft and nested chambers surroundin said shaft, said chambers being subdivided into radial groups of flnes connected in series, a channel connected with the lower end of the shaft to supply cold air thereto or to carry away combustlon products individually regulatable means for supplying air and fuel to the lower portions of the outermost flues of the several groups, and individually regulatable means for carrying the hot blast away from the outermost flues at points above the fuel inlets and air inlets.

2. An air-blast heater comprising walls forming a central shaft and nested chambers surrounding said shaft, said chambers being subdivided into radial groups of flues connected in series, a channel connected with the lower end of the cold air thereto or carry away combustion products, individually regulatable air-heating channels located in the outermost wall and connected with the lower portions of the outermost flues, individually regulatable means for supplying fuel to the lower po-rtions of said outermost flues, and individually regulatable means for carrying the hot blast away from the outermost flues at points above the fuel inlets and air inlets.

3. An air-blast heater comprising walls forming a central shaft and nested chambers surrounding said shaft, said chambers shaft to supply above the fuel inlets being subdivided into radial groups of flues connected in series, a channel connected with the lower end of the shaft to supply cold air thereto or carry away combustion products, individually regulatable air-heating channels located in the outermost wall, each of said channels comprising'an ascending portion connected with the air inlet and a descending portion, ofsmaller cross sec tion than the ascending ortion, connected with the lower portion of one of the outer-. most flues, individually regulatable means for supplying fuel to the lower portions of said outermost flues, and individually regu latable means for carrying the hot blast away from the outermost flues at points and air inlets.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

EDMUND HOHMANN. Witnesses L. C. FLACGUS, JOHN LOTKA.

copies at this patent may be obtained for five cents each, by addressing the Commissioner of latents,

. Washington, D. G. 

